From 2019 to 2021, the child poverty rate in the United States (US) declined by more than 50 percent, largely due to the temporary provision of an unconditional child allowance. This research note uses micro-data from more than 50 countries, and US data spanning more than 50 years, to place the 2021 child poverty rate in historical and international perspective. We demonstrate that whether using the Supplemental Poverty Measure (SPM) or relative poverty measures, the US child poverty rate in 2021 was at its lowest level since at least 1967. The US tax and transfer system reduced the 2021 SPM child poverty rate by more than 75 percent relative to the pre-tax/transfer child poverty rate, three times greater than its mean reduction effect between 1967-2019. Internationally, the temporary child allowance in the US reduced its 2021 child poverty rate from the 80th percentile to the 40th percentile among all countries examined. From 2019 to 2021, the relative US child poverty rate fell from a level comparable to Bulgaria to a level comparable to Germany. Moreover, the US tax and transfer system progressed from reducing child poverty at a rate comparable to Peru in 2019 to a rate comparable to Norway in 2021.